'use strict';

/**
 * WaterWave - Water ripples post processing
 *
 * @object
 */

module.exports = {
  name: 'WaterWave',
  paramsTypes: {},
  defaultParams: {},
  glsl: `
  #define PIS 3.1415926

  vec3 mod289(vec3 x) {
    return x - floor(x * (1.0 / 289.0)) * 289.0;
  }
  vec4 mod289(vec4 x) {
    return x - floor(x * (1.0 / 289.0)) * 289.0;
  }
  vec4 permute(vec4 x) {
    return mod289(((x*34.0)+1.0)*x);
  }
  vec4 taylorInvSqrt(vec4 r){
    return 1.79284291400159 - 0.85373472095314 * r;
  }

  float snoise(vec3 v) {
    const vec2  C = vec2(1.0/6.0, 1.0/3.0) ;
    const vec4  D = vec4(0.0, 0.5, 1.0, 2.0);

    vec3 i  = floor(v + dot(v, C.yyy) );
    vec3 x0 =   v - i + dot(i, C.xxx) ;

    vec3 g = step(x0.yzx, x0.xyz);
    vec3 l = 1.0 - g;
    vec3 i1 = min( g.xyz, l.zxy );
    vec3 i2 = max( g.xyz, l.zxy );

    vec3 x1 = x0 - i1 + C.xxx;
    vec3 x2 = x0 - i2 + C.yyy; // 2.0*C.x = 1/3 = C.y
    vec3 x3 = x0 - D.yyy;      // -1.0+3.0*C.x = -0.5 = -D.y

    i = mod289(i);
    vec4 p = permute( permute( permute(
        i.z + vec4(0.0, i1.z, i2.z, 1.0 ))
      + i.y + vec4(0.0, i1.y, i2.y, 1.0 ))
      + i.x + vec4(0.0, i1.x, i2.x, 1.0 ));

    // Gradients: 7x7 points over a square, mapped onto an octahedron.
    // The ring size 17*17 = 289 is close to a multiple of 49 (49*6 = 294)
    float n_ = 0.142857142857; // 1.0/7.0
    vec3  ns = n_ * D.wyz - D.xzx;

    vec4 j = p - 49.0 * floor(p * ns.z * ns.z);  //  mod(p,7*7)
    vec4 x_ = floor(j * ns.z);
    vec4 y_ = floor(j - 7.0 * x_ );    // mod(j,N)

    vec4 x = x_ *ns.x + ns.yyyy;
    vec4 y = y_ *ns.x + ns.yyyy;
    vec4 h = 1.0 - abs(x) - abs(y);

    vec4 b0 = vec4( x.xy, y.xy );
    vec4 b1 = vec4( x.zw, y.zw );

    vec4 s0 = floor(b0)*2.0 + 1.0;
    vec4 s1 = floor(b1)*2.0 + 1.0;
    vec4 sh = -step(h, vec4(0.0));

    vec4 a0 = b0.xzyw + s0.xzyw*sh.xxyy ;
    vec4 a1 = b1.xzyw + s1.xzyw*sh.zzww ;

    vec3 p0 = vec3(a0.xy,h.x);
    vec3 p1 = vec3(a0.zw,h.y);
    vec3 p2 = vec3(a1.xy,h.z);
    vec3 p3 = vec3(a1.zw,h.w);

    vec4 norm = taylorInvSqrt(vec4(dot(p0,p0), dot(p1,p1), dot(p2, p2), dot(p3,p3)));
    p0 *= norm.x;
    p1 *= norm.y;
    p2 *= norm.z;
    p3 *= norm.w;

    vec4 m = max(0.6 - vec4(dot(x0,x0), dot(x1,x1), dot(x2,x2), dot(x3,x3)), 0.0);
    m = m * m;
    return 42.0 * dot( m*m, vec4( dot(p0,x0), dot(p1,x1), dot(p2,x2), dot(p3,x3) ) );
  }

  vec3 curlNoise( vec3 p ){
    const float e = 0.1;
    float  n1 = snoise(vec3(p.x, p.y + e, p.z));
    float  n2 = snoise(vec3(p.x, p.y - e, p.z));
    float  n3 = snoise(vec3(p.x, p.y, p.z + e));
    float  n4 = snoise(vec3(p.x, p.y, p.z - e));
    float  n5 = snoise(vec3(p.x + e, p.y, p.z));
    float  n6 = snoise(vec3(p.x - e, p.y, p.z));

    float x = n2 - n1 - n4 + n3;
    float y = n4 - n3 - n6 + n5;
    float z = n6 - n5 - n2 + n1;

    const float divisor = 1.0 / ( 2.0 * e );
    return normalize( vec3( x , y , z ) * divisor );
  }

  vec4 transition (vec2 uv) {
    float iTime = progress * PIS/2.0;
    float f = sin(iTime) ;
    vec3 curl = curlNoise(vec3(uv,1.) *5. + iTime) / 1.;

    vec4 t0 = getFromColor(vec2(uv.x,uv.y + f * (curl.x) ) );
    vec4 t1 = getToColor(vec2(uv.x,uv.y + (1.-f) * (curl.x) ));
  
    uv.x += curl.x;
    return mix(t0,t1,f);
  }
`,
  author: 'anonymous',
  createdAt: 'Mon, 12 Jun 2020 12:52:34 +0800',
  updatedAt: 'Mon, 12 Jun 2020 12:52:34 +0800',
};
